linux-kernel - [tip: locking/core] locking/ww_mutex: Abstract out mutex accessors

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Message-ID: <162923125110.25758.3399929616125299500.tip-bot2@tip-bot2>
Date:   Tue, 17 Aug 2021 20:14:11 -0000
From:   "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: locking/core] locking/ww_mutex: Abstract out mutex accessors

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     9934ccc75cec2bafac552c2130835630530c4f7e
Gitweb:        https://git.kernel.org/tip/9934ccc75cec2bafac552c2130835630530c4f7e
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Sun, 15 Aug 2021 23:28:49 +02:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Tue, 17 Aug 2021 19:04:57 +02:00

locking/ww_mutex: Abstract out mutex accessors

Move the mutex related access from various ww_mutex functions into helper
functions so they can be substituted for rtmutex based ww_mutex later.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Link: https://lore.kernel.org/r/20210815211304.622477030@linutronix.de
---
 kernel/locking/ww_mutex.h | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/kernel/locking/ww_mutex.h b/kernel/locking/ww_mutex.h
index f5aaf2f..842dbed 100644
--- a/kernel/locking/ww_mutex.h
+++ b/kernel/locking/ww_mutex.h
@@ -53,6 +53,18 @@ __ww_waiter_add(struct mutex *lock, struct mutex_waiter *waiter, struct mutex_wa
 	__mutex_add_waiter(lock, waiter, p);
 }
 
+static inline struct task_struct *
+__ww_mutex_owner(struct mutex *lock)
+{
+	return __mutex_owner(lock);
+}
+
+static inline bool
+__ww_mutex_has_waiters(struct mutex *lock)
+{
+	return atomic_long_read(&lock->owner) & MUTEX_FLAG_WAITERS;
+}
+
 /*
  * Wait-Die:
  *   The newer transactions are killed when:
@@ -157,7 +169,7 @@ static bool __ww_mutex_wound(struct mutex *lock,
 			     struct ww_acquire_ctx *ww_ctx,
 			     struct ww_acquire_ctx *hold_ctx)
 {
-	struct task_struct *owner = __mutex_owner(lock);
+	struct task_struct *owner = __ww_mutex_owner(lock);
 
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -253,7 +265,7 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
 	 * __ww_mutex_add_waiter() and makes sure we either observe ww->ctx
 	 * and/or !empty list.
 	 */
-	if (likely(!(atomic_long_read(&lock->base.owner) & MUTEX_FLAG_WAITERS)))
+	if (likely(!__ww_mutex_has_waiters(&lock->base)))
 		return;
 
 	/*